1. Technical Field
The present invention relates to a touch panel.
2. Description of the Related Art
With the development of computers using digital technology, devices assisting the computers have also been developed, and personal computers, portable transmitters and other personal information processors execute processing of text and graphics using a variety of input devices such as a keyboard, a mouse and so on.
While the rapid advancement of an information-oriented society has been widening the use of computers more and more, there have been occurring the problems of it being difficult to efficiently operate products using only the keyboard and mouse as being currently responsible for the input device function. Thus, the demand for a device that is simple, has minimal malfunction, and has the capability to easily input information is increasing.
Furthermore, current techniques for input devices exceed the level of fulfilling general functions and thus are progressing towards techniques related to high reliability, durability, innovation, designing and manufacturing. To achieve this purpose, a touch screen has been developed as an input device capable of inputting information such as text and graphics.
The touch screen is mounted on the display surface of an image display device such as an electronic organizer, a flat panel display including a liquid crystal display (LCD), a plasma display panel (PDP), an electroluminescence (El) device or the like, or a cathode ray tube (CRT), so that a user selects the information desired while viewing the image display device.
The touch screen can be classified into a resistive type, a capacitive type, an electromagnetic type, a surface acoustic wave (SAW) type, and an infrared type. These various types of touch screens are adapted to electronic products in consideration of signal amplification problems, resolution differences, the degree of difficulty of designing and manufacturing technology, optical properties, electrical properties, mechanical properties, environment-resistant properties, input properties, durability, and economic feasibility. Currently, the resistive touch panel and the capacitive type touch panel are prevalently used in a broad range of most fields.
The resistive type touch panel has a configuration in which upper/lower transparent electrode films are disposed such that they are spaced apart from each other by a spacer, and they are contactable with each other by user touch. When an upper touch panel in which an upper transparent electrode film is formed is pressed by an input unit, such as, a finger, a pen, or the like, upper/lower transparent electrode films are conducted and a controller senses a change in voltage due to a change in resistance value at the position and thus recognizes the touched coordinate. As the resistive type of touch panel, there are a digital resistive type of touch panel and an analog resistive type of touch panel.
In the capacitive type touch panel, an upper substrate in which a first electrode pattern is formed, and a lower substrate in which a second electrode pattern is formed, are spaced from each other, and an insulator is inserted therebetween to prevent the first electrode pattern and the second electrode pattern from being contacted with each other. In addition, the upper substrate and the lower substrate are provided with electrode wirings connected to the electrode patterns. The electrode wirings transfer the change in capacitance, which is generated between the first electrode pattern and the second electrode pattern when a touch screen is pressed by the input unit, to a controller.
Here, the touch panel may be divided into an active area and a bezel area surrounding the active area. When an image display device is coupled with a lower part of a touch panel, an image generated in the image display device passes through the active area, but not the bezel area. Transparent electrodes for recognizing a point touched by the user therethrough are formed in the active area, and electrode wires for applying electric power therethrough are formed in the bezel area.
In cases of the touch panel of the prior art, there was a technical limitation in that the space between electrode wirings can not be reduced to several tens of an or less because short circuits may occur between the electrode wirings. Therefore, when plural electrode wirings are formed, an area where the electrode wirings occupied was increased due to a predetermined space between the electrode wirings. As a result, the increase of an electrode wiring area means an increase of the bezel area, with the result that the active area is relatively decreased in a restricted size of the touch panel. Furthermore, the increase of the bezel area prevented the touch panel from being downsized.